Surface Texture Instrument Research Articles

Development and Evaluation of New Material Measure with Chirp Form for Surface Texture Instruments

This study designs and develops a new material measure with a chirp form. Material measures are measurement standards for calibration, verification, and inspection. Since material measures are essential for ensuring the traceability of surface texture instruments, we have been developing a manufacturing system to provide them. ISO 5436-1:2000 contains material measures with sinusoidal wave forms, random wave forms, triangular wave forms, trapezoidal wave forms, cusp forms, rectangular forms, etc. However, ISO 5436-1:2000 does not contain a material measure with a chirp (sweep) form. Therefore, we propose a material measure with a chirp form. Chirp signals are frequently used for various analyses in the fields of mechanical engineering, electrical engineering, physics, and others. The primary purpose of the proposed material measure with a chirp form is to rapidly and simply examine the characteristics and capabilities of implemented Gaussian filters. We designed the surface form of the material measure as a logarithmic chirp form to maximize the utility of the primary purpose in this study. The wavelength of the manufactured chirp form varies logarithmically in the lateral (x) direction. This paper presents the following five points: 1) the design and development of the material measure with a chirp form, 2) the application of the proposed material measure to the examination of the attenuation characteristics of implemented Gaussian filters, 3) the application of the proposed material measure to obtain the deformation of the roughness form due to the implemented Gaussian filters, 4) the application of the proposed material measure to specify the algorithm of the implemented Gaussian filters, and 5) the possibility of another application of the material measure with a chirp form.

An international comparison of surface texture parameters quantification on polymer artefacts using optical instruments

An international comparison of optical instruments measuring polymer surfaces with arithmetic mean height values in the sub-micrometre range has been carried out. The comparison involved sixteen optical surface texture instruments (focus variation instruments, confocal microscopes and coherent scanning interferometers) from thirteen research laboratories worldwide. Results demonstrated that: (i) Agreement among different instruments could be achieved to a limited extent; (ii) standardised guidelines for uncertainty evaluation of areal surface parameters are needed for users; (iii) it is essential that the performance characteristics (and especially the spatial frequency response) of an instrument is understood prior to a measurement.

Development of low-cost material measures for calibration of the metrological characteristics of areal surface texture instruments

In this paper, the development of a number of material measures, which are designed to allow users to calibrate areal surface texture instruments, is presented. The material measures include grid structures, for the determination of the amplification, linearity and squareness of the x, y and z-axes, and star patterns, for the determination of the lateral period limit. Relatively complex methods of manufacture have been used to produce master artefacts, which are then replicated to produce cost-effective material measures for users. The process chain for the material measures is presented along with the methods used to calibrate them.

Relationship between tool flank wear area and component forces in single point turning

This paper describes the relationship between flank wear area and cutting forces for turning operations. A set of experiments were performed on a CNC lathe without coolant. The CNMG120412N-UJ tool insert was used to cut low alloy steel (AISI 4340). Flank wear surface area was measured by surface texture instrument (Form Talysurf™ series) using a software package. Cutting forces were measured by a Kistler™ piezo-electric dynamometer. The experimental results show that there is an increase in the three directional components of the cutting force with increase in flank wear area. Among the three cutting forces measured, the tangential force is the largest while the radial force is the smallest. However, when the tool insert begins to fail, all the three cutting forces increase sharply, especially so for the axial and radial cutting forces. The radial force was also found to be slightly larger than the axial force when tool begins to fail. This paper also presents mathematical modeling for better understanding of the relationship between flank wear area and cutting forces. The mathematical models were solved by Matlab.

Topography of the flank wear surface

In many applications, topography represents the main external features of a surface. This paper describes the topography of the flank wear surface and also presents the relationship between the maximum flank wear and the topography parameters (roughness parameters) of the flank wear surface during the turning operation. A modern CNC lathe machine (Okuma LH35-N) was used for the machine turning operation. Three-dimensional surface roughness parameters of the flank wear surface were measured by a surface texture instrument (from Talysurf series) using surface topography software (Talymap). Based on the resulting experimental data, it is found that as the flank wear increases, the roughness parameters (sR a, sR q, and sR t) on the flank surface increase significantly. The greater the roughness value of the flank wear surface, the higher the friction of the tool on the workpiece and the greater the heat generation that will occur, thus ultimately causing tool failure. On the other hand, positive skewness (sR sk) indicates the presence of a small number of spikes on the flank surface of the cutting tool, which could quickly wear off during the machining process.

An algorithm to extract critical points from lattice height data

The data measured on areal surface texture instruments often takes the form of height values on a discrete rectangular lattice. The definitions of critical points (peak, pit and saddle points) for this type of data is a very important issue for definitions and stable algorithms of areal texture parameters. Many of the published algorithms for critical points fail to meet some very simple topological properties which are always true for continuous data. Thus the collection of critical points produced from these published algorithms could not have come from a genuine continuous surface giving difficulties with interpretation of the results. An algorithm for critical points from lattice height data is presented which satisfies these topological properties and represents genuine features from the measured surface.

Friction and wear characteristics of aluminum bronze coatings on steel substrates sprayed by a low pressure plasma technique

In the present research work, the tribological characteristics of low pressure plasma sprayed aluminum bronze coatings against steel ball (SUJ2), have been studied. The effects of different loads, as well as high speed and boundary lubrication conditions, have been examined using the sliding tester. The films were synthesized using a low-pressure plasma spraying technique under different operating conditions. The correlation between the processing variables and the tribological characteristics of the resulting aluminum bronze coatings has been studied. Optical and scanning electron microscopy was employed to evaluate the morphology of the coating’s microstructures. The depths of the wear tracks were evaluated using surface texture instrument. The results indicate that under optimum operating conditions, the test samples exhibit a dense microstructure with a high hardness, low coefficient of friction and high wear resistance. Moreover, the strength of the interface between the film and the substrate was found to be adequate for many industrial applications. The range of optimum operating conditions has also been identified.

Interfacial crystallization of isotactic polypropylene molded against the copper surface with various surface roughnesses prepared by an electrochemical process

The influence of surface topography of copper (Cu) sheet on the heterogeneous nucleation of isotactic polypropylene (iPP) at the iPP/Cu interface had been investigated mainly using polarized optical microscope with hot stage. Various textures of Cu surfaces prepared by sandpaper polishing and electrochemical anodizing had been made and they were utilized to induce interfacial nucleation of iPP upon supercooling. This process enables us to change the topological feature of the copper surface without changing their chemical compositions. The pretreated surfaces were quantitatively characterized by a surface texture instrument in terms of RMS roughness (Ra). Copper surface with higher surface roughness induced more nuclei of iPP and led to a thicker transcrystalline layer in the interfacial region upon supercooling over the temperature range 128°C < Tc < 134°C. Based on the theory of heterogeneous nucleation, it was found that the induction time correlates well with the nucleation rate in determining the interfacial free energy difference function Δσ of iPP. The ratio of Δσ at the interface to that in the bulk matrix (ΔσTCL/Δσbulk) for the polished surface (Ra = 0.09 μm) is 2.89, implying the transcrystallization growth is unfavorable from a thermodynamic point of view. The ratio of ΔσTCL/Δσbulk becomes smaller as the current density for anodizing increases, indicating the transcrystallization growth is getting favorable. Moreover, induction times and nucleation rates were also measured to characterize quantitatively the nucleating ability of various Cu surfaces.

Effect of the surface roughness of sulfuric acid-anodized aluminum mold on the interfacial crystallization behavior of isotactic polypropylene

The influence of the surface topography of aluminum alloy (Al) on the heterogeneous nucleation of isotactic polypropylene (iPP) at the iPP/Al interface has been investigated using a polarized optical microscope (POM) with a hot stage. Different textures of the Al surface were prepared by electrochemical processes, including polishing and anodizing, and utilized to induce interfacial nucleation upon supercooling. This process enabled the topological features of the aluminum surface to be controlled without altering their chemical composition by such a procedure. The pretreated surfaces were investigated by scanning electron microscopy and quantitatively characterized by a surface texture instrument in terms of RMS roughness (R a). The Al surface with a higher surface roughness induced more nuclei of iPP and led to a transcrystalline layer (TCL) in the interfacial region upon supercooling over the temperature range 128°C < T c < 154°C. Based on the theory of heterogeneous nucleation, it was found that the induction time correlates well with the nucleation rate in determining the interfacial free energy difference function Δσ of iPP. The ratio of Δσ at the interface to that in the bulk matrix (ΔσTCL/Δσ bulk) for the polished surface (R a = 0.38 μm) is 4.45, implying that transcrystallization growth is unfavorable from a thermodynamic point of view. On the other hand, the Δσ TCL/Δσ bulk ratio decreases as the current density for anodizing increases, indicating that transcrystallization growth becomes favorable. The induction times and nucleation rates were also measured to characterize quantitatively the nucleating ability of various Al surfaces. The oxide porosity was filled in when sealing treatment by hydration was carried out. This resulted in Δσ TCL/Δσ bulk being slightly higher as the surface roughness decreased.

Surfascan 3D — An industrial 3D surface texture characterisation instrument

2D profile analysis has often in the past been considered sufficient to control the geometrical features of a surface and to ensure that they are compatible with the required functionalities. Yet, experience shows that 3D surface texture analysis is now essential wherever a complete assessment of the surface is required to enable the selection of the most appropriate surface texture to achieve a required functionality. This paper introduces measurement strategies and features considered as essential by SOMICRONIC when designing or developing 3D surface texture measuring instruments, knowing that the pursued aim is to assess the measured surface in a way to reveal the real surface. This is achieved without losing sight of existing ISO standardized concepts concerning surface texture profile analysis. Indeed, essentially for economical reasons, we consider that 31) surface texture stylus instruments must be designed to achieve classical surface texture profiles measurements and characterisations and to fulfil conditions and characteristics listed and described in existing surface texture ISO standards. We propose to develop in the next paragraphs, the following points: • - Design of the data acquisition unit of a 3D surface texture instrument • - Strategy for the measurement of the surface • - Application of these concepts - Examples.

Machining of Hard Materials

An international comparison of optical instruments measuring polymer surfaces with arithmetic mean height values in the sub-micrometre range has been carried out. The comparison involved sixteen optical surface texture instruments (focus variation instruments, confocal microscopes and coherent scanning interferometers) from thirteen research laboratories worldwide. Results demonstrated that: (i) Agreement among different instruments could be achieved to a limited extent; (ii) standardised guidelines for uncertainty evaluation of areal surface parameters are needed for users; (iii) it is essential that the performance characteristics (and especially the spatial frequency response) of an instrument is understood prior to a measurement.

Photoetching of narrow deep slots for stylus wear standards

The performance of surface texture instruments needs to be assessed periodically. Although a step height standard checks vertical magnification and an R a standard checks mathematical integration, no stylus wear standard was available for checking resolution. Such a standard has now been produced with vertical-walled slots of widths 2.5, 5, 10 and 20μm, and a minimum depth of 42.4μm, made by anisotropic photoetching of polished silicon slices. During exposure of photoresist the slots were aligned with a crystal cleavage plane to control line width and this was achieved using a circular table to orientate the slice with a chrome-on-glass mask. These stylus wear standards are now commercially available